Some thoughtful researchers have also presented empirical data (Clifford & Wendell 2015). Although interesting and suggestive, these data show only a weak, uneven correlation between popular attitudes toward vaccination & disgust sensitivity.

If disgust “drives” antivax sentiment, then presumably disgust’s influence on vaccine attitudes should “look like” its influence on other policy and risk attitudes that we have good reason to think are disgust driven. By “look like” I mean should have a comparably strong effect, and be in the same direction as the impact of disgust on these attitudes and policies.

By the same token, it disgust is a meaningful influence on vaccine attitudes, then the relationship between the two shouldn’t “look like” the relationship, or basically nonrelationship, that exists between disgust and policy and risk attitudes that we have good reason to think aren’t disgust driven.

This sort of external validation test is essential given how spotty the reported correlations are between disgust sensitives and vaccine attitudes.

Well, some colleagues and I collected data that enables this sort of evaluation. In my view, it weights strongly against the asserted disgust-antivax thesis.

There are more data than I’ll present today, but for a start, consider how disgust relates to support for the policy of mandatory universal childhood immunization.

To measure disgust, we used the conventional “pathogen disgust” scale, which other researchers (Clifford & Wendell 2015) have reported to be correlated with vaccine attitudes.

To measure subjects’ attitudes toward mandatory universal childhood immunizations, we asked them to tell us on a six-point scale how strongly they supported or opposed “requiring children who are not exempt for medical reasons to be vaccinated against measles, mumps, and rubella.”

To enable the comparison that I described, we also measured how strongly subjects supported or opposed a collection of other policies that one would expect to be either related or unrelated to disgust sensitivities.

In relation to the former, we observed the expected result. Disgust sensitives (modestly) predicted opposition to gay marriage and legalization of prostitution.

They also predicted support for making Christianity the “official religion” of the US and for imposing the death penalty for murder, policies that reflect moral evaluations—“purity” in connection with the former and “punitiveness” in relation to the latter (e.g., Stevenson et al. 2015)—that are understood to have a nexus with disgust.

Likewise we observed that disgust sensitivities were inert in relation to policies one would expect not to be related to disgust. There was no meaningful relationship between disgust, e.g., and support for raising taxes for the wealthiest Americans, for legalizing on-line poker, or for amending the Constitution to permit prohibiting corporate campaign contributions.

Okay, then. So what about universal mandatory vaccination?

Well, contrary to the disgust-antivax thesis, It turned out that there was no meaningful relationship between support or opposition to that policy and disgust, as reflected in this standard measure. Indeed, the very small effect we observed was in the opposite direction from what that thesis posits—that is, as disgust sensitivities increased, so did support for universal immunization, although by a factor no serious researcher would take seriously (r = 0.07, p < 0.05).

raw data-- eat, eat! [click, click!]In sum, the relationship between disgust sensitives and vaccine policy attitudes “looks” identical to the relationship between disgust and policies disgust-unrelated policies and nothing like the relationship between disgust and disgust-related ones. Not what one would expect to see in the evidence if in fact the disgust-antivax hypothesis were correct.

There’s more, as I said. I’ll get to it “tomorrow.”

But if disgust doesn’t drive antivax sensibilities, what does?

The answer, I think, is that nothing systematically does.

Contrary to the popular media trope, there is tremendous support for mandatory vaccination in the US (Kahan 2016; CCP 2014; Kahan 2013)—a point I’ve stressed repeatedly in this blog & that is reaffirmed by the 80%-level of support reflected in the policy item featured here.

mmmmm ... regressions... click for a bite!There are segments of society who feel otherwise. But they are small in number and more importantly consist of people who are outliers in any cultural group of which they are a part.

For that reason, what “drives” anti-vaccine sentiment will always evade detection by broad-based survey techniques.

To help address the problem of vaccine hesitancy—and it is a problem, even if it is confined to opinion-group fringes and geographic enclaves--researchers shouldn’t be using survey methods but should instead by using more fine-grained tools like behaviorally validated screening instruments (Opel et. al. 2013).

This is one of the points made in an excellent report recently by the Department of Health and Human Service’s National Vaccine Advisory Committee (2015).

Reader Comments (1)

In my opinion, given the conclusions above, we can now start with the idea that "vaccine hesitancy [is] a “boutique” risk perception" and proceed onward. One of the results of that realization is that, circling back, x-y plots like the ones above don't yield much information and some other visualization method is needed.

In the case of anti-vaccine sentiment, I think a better model would be a few islands on an otherwise fairly smoothly compliant and complacent sea. And even when looking at the groups associated with the anti-vaxx islands, most of the group is not in opposition and stays safely below (fully vaccinated) sea level. Part of public health efforts needs to be in keeping the islands as small as possible. And in figuring out how to avoid the spread of infections from island to island or into the rest of society.

Several of the groups are subsets of very fundamentalist Christian groups. Some Old Order Amish and some Dutch Reformed Church groups oppose vaccines. But these groups are not evangelical. And they stand apart from government. (Thus they would not, IMHO, answer a question about making Christianity an official government function in the manner that other evangelical Christian groups might. Thus confounding the interpretation of the data above). An outbreak of measles I am familiar with in 2014 centered in a Dutch Reformed community in British Columbia, Canada, was started by travel to the "Dutch Bible Belt" of The Netherlands.

More attractive from the left, Waldorf schools teach based on a spiritual mysticism with some roots in Christianity, that is based on the philosophy of Rudolf Steiner, called Anthroposophy. In my experience, many people who send their kids to these schools do so because they are very attracted by the emphasis on play, imagination, an experiential appreciation of nature, and a slowness or lack of pressure to get to the 3 R's of conventional schooling. These often are people who are associated with alternative medicine themselves or find such practices attractive. In my experience, they are usually not very conversant on the details of Anthroposophy. Some but not all, oppose vaccines. These people have little in common with Christian fundamentalists in most ways.

Additionally, there are immigrant groups who may have limited access to the US health system and while these communities do not oppose vaccines they may contain many adult as well as children who have not been vaccinated.

A lot of Americans lead busy, time pressured lives. Unlike in times past, where there were more public health clinics offering vaccines and school nurses in schools coordinating student vaccine history, these days it is more up to the parents to get their kids to a medical professional for immunization services. This is not an easy thing for many hourly workers to accomplish.

Groups like the ones above are concerning to society at large because they can serve as disease reservoirs. A lot can be accomplished by expanding acess to heath clinics. The problem is well known to public health officials, and there are, at least after the fact of an outbreak, fairly effective measures that can be taken to not only contain the spread of disease within these communities, but also to use the outbreak as a mechanism to entice individual members of the religious sects and other groups who oppose vaccines to get their own kids vaccinated. The situation I am most familiar with was the measles outbreak mentioned above, centered in Chiliwack, BC. Effective vaccination programs require, not waves of derision aimed at the groups, but the establishment of confidential clinics with assurances to parents that they can bring their children in without questions or recrimination over past lack of vaccines.

Perhaps the most concerning islands out there, spewing toxic fumes in a manner that could affect the rest of society, are composed of elites in areas like Marin County, CA. I believe that these people are used to being in charge and feel that they are privileged in ways that leave them exempt from many of the concerns of ordinary folks. In my opinion, the medical professionals who establish practices to serve these upscale communities are of a similar ilk. These are people with excellent medical access but also excellent media access. They are also capable of making a lot of noise that poses the danger of influencing others. This out-sized influence, in my opinion, distorts and poisons a science based conversation on vaccines and public health.

In that regard, one of my concerns with the current state of science communication regarding vaccines is the publicity surrounding what I see as a basically a very optimistic and positive report on vaccines put out by the American Academy of Pediatrics. The report highlights the very influential role played by parent's personal pediatricians in influencing even those that are hesitant to get their children vaccinated. http://pediatrics.aappublications.org/content/early/2016/08/25/peds.2016-2146. But the part that is getting highlighted in many social media outlets has to do with dismissal of parents from a pediatrician's practice if they continue to refuse vaccinations. My concerns are twofold. First, this publicity, as assimilated by vaccine hesitant parents before they even get to the pediatricians office may cause them simply not to get to a paediatricians office in the first place. Secondly, pediatricians are human also and under the stress and time pressure of many practices, they may dismiss patients who might, with enough time, attention and effort be convinced to change their positions. The net result would be an increase in the reservoir of unvaccinated children.

Are there small islands of "disgust"? I do think that there is a general aversion to needles. The link is now lost to me but there was once an excellent article online by a pediatrician discussion the rocky and abrupt transition from obstetrician to pediatrician in modern practices. (as opposed to the now very distant family doctor handling it all). Vaccines come up at the first well baby visits. It is also true that for many Americans frequent job transitions even without moves make for a need to change insurance programs and thus doctors. In my opinion, people are more likely to accept a needle jab or any painful or difficult medical procedure if they trust the nurse or practitioner. Maybe trust is more important than disgust.

Unrelated to disgust, but Dan does like statistics: I think that we need to re-calibrate our herd immunity concepts for the modern global era. Some of the above islands are nuisances mostly to themselves But there are interactions outward. Presumably the measles virus that infected people in British Columbia made it from Europe by airline travel. In the immediate aftermath of the measles outbreak at Disneyland, Disney corporate executives sent lobbyists rushing to the California State capitol to ensure that blame was not sent their direction. One thing that is true of a place like Disneyland is that so many people are brought into fairly intimate contact from original locations worldwide. These potential exposures have no relationship to the concept of potential exposure levels of one infected individual. http://cid.oxfordjournals.org/content/52/7/911.full.pdf+html. I think for measles the level of RO was 12 to 18. We need to look at high exposure venues like Disneyland and airports. Additionally, we need to figure out how to handle infants and immune impaired individuals. And we ought to have at the very least, hospitals and clinics operating at a contagion control level at which they, or at least sections of the institutions, can be considered safe zones.

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